Auston Matthews took responsibility on behalf of his Toronto Maple Leafs after their collapse against the Ottawa Senators on Monday night.

"We just got a little lackadaisical. ... We definitely blew this one, for sure," Matthews said following a 6-5 overtime loss, according to The Athletic's James Mirtle.

Matthews' second goal of the game gave the Maple Leafs a 5-1 lead in the final minute of the second period, but the Senators rallied with a goal of their own before the intermission and then three more in the third. Evgenii Dadonov tied it with just over two minutes left in regulation and then won it for Ottawa in overtime.

Maple Leafs head coach Sheldon Keefe believes Toronto's problems began before the team jumped out to a four-goal lead.

"It started before 5-1," the bench boss said, according to the Toronto Sun's Lance Hornby. "(We were) careless. (There was) something creeping into our game. We gave it to them."

"They only got what we gave them," Keefe added.

Monday marked the first time in franchise history the Senators overcame a four-goal deficit. They were previously 0-237-3 after falling behind by that margin.

Toronto had a 99.97% chance to win after Matthews' second goal, according to The Athletic's Dom Luszczyszyn.

The superstar's markers were his NHL-leading 12th and 13th of the season.

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